Constant tension controller device for winder

ABSTRACT

A constant tension controller device for a winder which comprises a differential transformer for generating an output voltage in response to a vertically movable roller moved up and down according to the tension of a yarn, and a tacho-generator connected with a three-phase induction motor for driving a spool for rotation, whereby electric current in one of three power lines of the three-phase induction motor is controlled by a thyrister as a function of the difference between the output voltage of the tacho-generator and the output voltage of the differential transformer so that the yarn of nylon or like material are wound on the spool with a constant tension.

United States Patent Tomimatsu [54] CONSTANT TENSION CONTROLLER DEVICE FOR WINDER [72] inventor: Yoshio Tomimatsu, Neyagawa-shi, Japan [73] Assignee: Matsushita Electric Industrial (20., Ltd.,

Osaka, Japan [22] Filed: Nov. 13, 1969 [21] Appl.No.: 876,284

[ 1 June 20, 1972 Primary Examiner-Stanley N. Gilreath Attorney-Stevens, Davis, Miller & Mosher ABSTRACT A constant tension controller device for a winder which comprises a differential transformer for generating an output voltage in response to a vertically movable roller moved up and down according to the tension of a yarn, and a tacho-generator connected with a three-phase induction motor for driving a spool for rotation, whereby electric current in one of three power lines of the three-phase induction motor is controlled by a thyrister as a function of the difference between the output voltage of the tacho-generator and the output voltage of the diflerential transformer so that the yarn of nylon or like material are wound on the spool with a constant tension,

4Clains,5DrawingHgui-es PATENTEnJunzo 1972 3,670,975 SHEET 10F 2 -INVENTOR YOSHIO TOMIMATSU TTORNEYS PATENTEDJUHZO m2 sum 20F 2 INVENTOR YOSHIO TOMIMATSU fizz/ Wm ATTORNEYS CONSTANT TENSION CONTROLLER DEVICE FOR WINDER This invention generally relates to a constant tension controller device for a winder, and more particularly to a constant tension controller device for a winder which is used to wind on a spool a very thin yarn of nylon, silk or like material in chemical fiber plants or spinning mills, and in which the output voltage of a differential transformer is varied by a vertically movable roller moved up and down by the tension of the yarn so that one of the three phases of a three-phase induction motor is quantitatively controlled by the difference between the output voltage of a'tacho-generator connected with the threephase induction motor and the output voltage of the differential transformer.

An example of the construction of the conventional constant tension controller device for a winder is shown in FIG. 4 of the accompanying drawings. The shown example of the conventional construction includes a speed setting auto-transformer 1 connected with a single-phase power source, a twophase motor 2 connected with the speed setting auto-transformer 1 through a phase-shifting capacitor 3 or the main winding 5 of a saturable reactor 4, a spool 6 driven by the twophase motor 2, a yarn 7 to be wound on the spool 6 by means of a fixed roller 8 and a vertically movable roller 9 which is pivotally attached to a supporting point 10 by means of an arm 11, a differential transformer 12 having its voltage varied with the displacement of the vertically movable roller 9, and a rectifier 13 for rectifying the voltage of the differential transformer 12. The saturable reactor 4 has a control winding 14 for controlling the flow of the current passing to the main winding 5 of the saturable reactor 4 in accordance with the output voltage of the rectifier 13. The yarn 7 fed at a predetermined speed via the fixed roller 8 and vertically movable roller 9 is wound on the spool 6 driven by the two-phase motor 2. Thus, any variation in the tension of the yarn 7 which may result from the swollen turns of the yarn on the spool or from any other extraneous force is converted into a voltage by the differential transformer 12 directly connected with the vertically movable roller 9 and the voltage is introduced into the control winding 14 of the saturable reactor 4 so that the output of the saturable reactor 4 becomes smaller as the yarn tension increases. For this purpose, the rotational speed of the two-phase motor 2 is lowered to reduce and control the yarn tension at a predetermined level. In case the two-phase motor 2 connected with the single phase power source is driven through the phase-shifting capacitor 3 as in the arrangement shown in FIG. 4, it is difficult to attain smooth control of the motor speed by using only one capacitor of this kind because another suitable capacitor is required for a different rotational speed of the motor. In some instances the two-phase motor may be driven from a three-phase power source through a T- connection transformer, but such an arrangement is disadvantageous in that the T-connection transformer is required and the power source must be large in size and sophisticated in construction thereby leading to a higher cost for the entire arrangement. In other instances, use is made of a V-connection three-phase motor connected with a three-phase power source in which one phase of the V-connection, is controlled; however such a V-connection motor is larger in size and more complicated in construction for the same output than the ordinary Y-connection motor or A-connection motor.

Alternatively, there are cases where the control is not effected by the input to the motor but by use of the excitation winding of an electromagnetic clutch directly connected to the motor so as to mechanically control the rotational speed of the motor, however, this results in a complicated arrangement and difficult maintenance thereof.

The present invention consists in inserting a main control means in one phase of a three-phase power source for con trolling the flow of current to be passed, connecting a threephase induction motor to the three-phase power source, comparing the output voltage of a differential transformer and the output of a tacho-generator in accordance with the variation in the tension of a yarn, varying the flow of current passing to the main control means in accordance with the degree of yarn tension, thereby controlling the number of revolutions of the three-phase induction motor and controlling the yarn tension at a predetermined level.

It is a first object of the present invention to provide a constant tension controller device which is capable of smoother speed control in a wider range by using a three-phase induction motor than by using a two-phase motor according to the prior art.

It is a second object of the present invention to provide a constant tension controller device which allows the use of a smaller, simpler and less expensive power source by employing a three-phase induction motor than by employing a twophase motor with a T-connection transformer according to the prior art. v I

It is a third object of the present invention to provide a constant tension controller device which is simply constructed and less expensive by using a three-phase induction motor than by using a V-connection motor according to the prior art.

It is a fourth object of the present invention to provide a constant tension controller device which is capable of detecting variation in the tension of a thin yarn of nylon or like material which is caused by the variable diameter of the turns of the yarn wound on a spool, by the variation in the source voltage for the three-phase induction motor or by any extraneous mechanical disturbance or like factor, and thereby comparing the detected variation in the yarn tension with the output voltage of a tacho-generator connected with the threephase induction motor.

It is a fifth object of the present invention to provide a constant tension controller device which provides speed control of the three-phase induction motor in a wider range by controlling one phase of the three-phase induction motor in accordance with the difference between the output of the differential transformer for detecting the tension of the yarn and the output of the tacho-generator.

It is a sixth object of the present invention to provide a constant tension controller device which is provided with a thyristor serving as the main control means for controlling one phase of the three-phase induction motor, whereby the flow of current to the thyristor is controlled.

It is a seventh object of the present invention to provide a constant tension controller device in which the power source side of a full-wave rectifier is connected as the main control means for controlling one phase of the three-phase induction motor so as to control the flow of current to the load of the full-wave rectifier to thereby control the flow of current to the three-phase induction motor.

These objects and features of the present invention will become fully apparent fromthe following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing the constant tension controller device for a winder according to an embodiment of the present invention;

FIG. 2 shows the electrical circuit of the constant tension controller device shown in FIG. 1;

FIG. 3 is a graph for illustrating the relationship between the number of revolutions and torque characteristic of the threephase induction motor used with the present invention;

FIG. 4 is a schematic diagram showing the constant tension controller device for a winder according to the prior art; and

FIG. 5 is a partial electrical circuit of another embodiment of the present invention.

Referring to FIG. 1, an embodiment of the present invention includes a spool 6, a yarn 7, a fixed roller 8, a vertically movable roller 9, a supporting portion 10, an arm 11, a differential transformer 12 and a rectifier 13, all these being conventional and similar to those shown by like numerals in FIG. 4. The difierential transformer 12 may be replaced by a synchro. The embodiment of the present invention further includes a three-phase induction motor 15 connected to a threephase voltage regulator 16, and a main control means 17 for controlling the input current of one phase of the three-phase induction motor main control means 17 may comprise semi-conductor elements such as thyristor or transistor which would reduce the size and improve the reliability and life. A tacho-generator 18 is directly connected with the three-phase induction'motor 15 and the voltage generated by the tachogenerator 18 is applied to the main control means 17 through a rectifier 19. A continuous thin yarn 7 of nylon or like material is wound on the rotating spool 6 and the diameter of the turns formed by the wound yarn on the spool 6 gradually increases as the winding operation progresses. The tension of the thin yarn to be wound on the spool 6 is varied with the variation in the voltage applied to the three-phase induction motor 15 or with any extraneous mechanical factor. If the tension of the thin yarn 7 to be wound on the spool 6 is constant the damage of the yarn will be minimized, whereas any excessive variation in the yarn tension would cause the thin yarn to be broken. Toprevent such an undesirable accident, the variation in the tension of the yarn 7 is converted into a variation in the output voltage of the differential transformer 12 through the vertically movable roller 9, and this output voltages is compared with the output voltage then provided by the tachogenerator 18 connected with the three-phase induction motor 15, thereby varying the flow of the current to the main control means. The flow of current passing to the main control means is in inverse proportion to the increase and decrease in the tension of the thin yarn 7.

Referring to FIG. 2, the electrical circuit used with the constant tension controller device according to the present invention includes a battery 20, resistors 21, 22 and 23 for providing the bias voltage of an oscillating transistor 24, a highfrequency bypass capacitor 25, primary and secondary windings 26 and 27 of an oscillating transformer, a tuning capacitor 28, and a capacitor 29 for feeding back a part of the oscillation voltage; The output voltage produced by the secondarywinding 27 of the oscillating transformer is low and must be amplified by an amplifier circuit at the next stage. The electrical circuit further includes a coupling capacitor 30, resistors 31, 32 and 33 for providing the bias voltage of an amplifier transistor 34, a high-frequency bypass capacitor 35, windings 36, 37 and 38 of a differential transformer 12, capacitors 39, 40 and 41 connected in parallel with the windings 36, 37 and 38 of the differential transformer 12, respectively, and an iron core 42 connected with the vertically movable roller 9 in such arelationship that the output voltage is entirely offset when the iron core 42 is in a predetermined position. The rectifier 13 includes diodes 43 and 44, smoothing capacitors 45 and 46, and resistors 47 and 48. Since the iron core 42 of the transformer 12 varies its position inaccordance with the positional variation of the vertically movable roller 9, the voltages appearing in the windings 37 and 38 are different in magnitude. Accordingly, the voltages applied to the resistors 47 and 48 are also different in magnitude and direction and are in such a relationship that they are ofiset by each other, while across the rectifier 13 there appears a differential voltage in a certain direction.

The circuit of FIG. 2 further includes a capacitor 49 for smoothing the rectified voltage of the tacho-generator 18, a resistor 50, a thyristor 51 inserted in a phase of the power source supplying the three-phase induction motor 15, a diode bridge 52 to which a voltage is applied when the thyristor 51 is in the OFF" state, a voltage dropping resistor 53, a constant voltage diode 54, a unijunction transistor 55 constituting the ignition circuit of the thyristor 51, a phase controlling transistor 56, stabilizing resistors 57 and 58, a pulse transfonner 59 whose secondary winding is connected with the control terminal of the thyristor 51, a capacitor 60 for determining the time constant, and resistors 61 and 62 for providing the bias voltage of the phase controlling transistor 56. The output voltage of the tacho-generator 18 is a dc. voltage of a predetermined direction, whereas the output voltage of the differential transformer 12 is a dc. voltage of a variable direction. Therefore, if the'flow of current to the phase controlling transistor 56 is controlled, the switching on of the unijunction transistor 55 is controlled so that the flow of current to the thyristor 51 is controlled by the secondary output of the pulse transformer 59. Instead of using the battery 20, it'

is practicable to use a three-phase power source having two phases thereof connected with a separate transformer and a rectifier to thereby provide a dc. voltage. The battery 20 is a dc. voltage source required to operate the oscillation circuit and differential transformer 12. Upon rotation of the threephase induction motor 15, the tacho-generator 18 and spool 6 are rotated. As the thin yarn such as nylon yarn is wound on the spool 6, the diameter of the turns of the wound yarn is increased to thereby vary the tension of the yarn portion left to be wound. It is important to maintain the tension of the yarn at a suitable value. If the iron core 42 fixed to thevertically movable roller 9 is moved up and down by the yarn, the output voltage appearing in thewinding 37 of the differential transformer l2 differs in magnitude and direction from the output voltage appearing in the winding 38 of the same transformer. On the other hand, the induced voltage produced by the tacho-generator 18 is rectified by the rectifier 19 so that the magnitude of the voltage is varied but the direction thereof remains fixed. The aforesaid two voltages are adjusted as described above, whereby the phase controlling transistor 56 has its operative state varied so as to control the switching on of the unijunction transistor 55. The voltage produced thereby in the secondary winding of the pulse transformer 59 controls the flow of current to the thyristor 51 which in turn controls the number of revolutions of the three-phase induction motor.

FIG. 3 illustrates the characteristics of one-phase control of the three-phase induction motor. The abscissa represents the number of revolutions N and the ordinate represents the torque T. Curve a" is the torque curve for the three-phase induction motor 15 and curves ,b, fc, d, 2" and f represent the torque curves for the three-phase induction motor 15 as it is subjected to negative feedback by the tachogenerator 18 and rectifier 19 so as to vary the set value of the speed. Curve g is the torque curve for the three-phase induction motor 15 as one of its phases is completelycut off. As seen from the graph of FIG. 3, the flow of current of one phase of the three-phase induction motor can be controlled over the range from curve (1" through curve Curve l. represents the torque requiredto provide a constant tension to the yarn 7 and theoretically this curve is a hyperbola. Curve fll represents the torque equivalent to the mechanical loss of the winder and curve III" is the composite torque curve comprising curves I" and 11". Hence, the composite curve III" is the curve actually required to provide a constanttension of the yarn 7 and the control is effected over the range from curve a to curve e, so as to broadly satisfy the composite curve III. The range between curves 0" and e is wide enough to select a suitable number of revolutions to provide a constant tension of the yarn 7.

Where a very thin yarn is wound by an ordinary yarn winder, the torque required to provide tension in the yarn becomes as small as the fraction of the torque equivalent to the mechanical loss and this fraction is smaller for thinner yarn. Thus, for thin yarns the torque of the load is practically represented by the mechanical loss. Therefore, with a winder for winding such a thin yarn, the composite torque of the load is always greater than the single-phase operating torque of the three-phase motor (curve g), whereby one-phase control is feasible. In the shown embodiment of the present invention, the thyristor 51 is provided in one line of the three-phase induction motor 15, and the conduction angle (firing angle) of the thyristor is controlled. Alternatively, as illustrated in FIG. 5, one power line to the motor 15 may be connected across the ac. terminals of a bridge-type rectifier, the thyristor 51' being connected across the dc. terminals of the rectifier and the motor current being controlled by controlling the firing angle of the thyristor. The gate and cathode of thyristor 51' are connected across the secondary winding of pulse transformer 59. Accordingly, as in the circuit of FIG. 2, the voltage produced across the secondary winding of transformer 59 when unijunction transistor 55 is switched on controls the flow of current through thyristor 51' which in turn controls the number of revolutions of the three-phase induction motor 15. As compared with the case where a two-phase motor is used, the present invention eliminates the need to use such power source means as a T-connection transformer. As compared with the case where a V-connection three-phase motor is used, the present invention allows the use of a smaller and less expensive motor, and as compared with the case where an electromagnetic clutch is used with the motor, the present invention ensures a lower cost and a longer life of the entire device. While the control of only one phase of the three-phase motor tends to become unstable unless the secondary resistance is great, the present invention solves this problem and ensures highly stable control by comparing the output voltage of the tacho-generator 18 with the output voltage of the differential transformer and effecting the one-phase control of the three-phase induction motor 15 in accordance with the difference between these two output voltages. Further, the present invention provides such a wide control range for the three-phase induction motor that stable control is ensured even if there is some fluctuation in extraneous factors such as source voltage variation or the like. Still further, the constant tension controller device provided by the present invention has a simplified construction, better perfonnance and is available at a lower cost than the conventional one. It will thus be appreciated that the present invention provides a constant tension controller device for a winder which can achieve better results than the prior art device.

What is claimed is:

l. A constant tension controller device for a winder comprising main control means (17) connected in series with one phase of a three-phase power source for controlling the flow of current therethrough,

a three-phase induction motor (15 connected to said threephase power source through said main control means (17) for driving a spool (6),

a vertically movable roller (9) mounted on an arm (11) supported pivotally at supporting point around which roller (9) yarn (7) is led from a supply reel through a fixed roll (8) to the spool (6),

a differential transformer (12) having an iron core (42) mechanically connected with said vertically movable roller 9) and having secondary windings (37, 38),

a rectifier (13), including diodes (43,44) and output resistors (47, 48) connected in series with said secondary windings (37,38) to produce across said series resistors (47, 48) a differential voltage in a predetermined direction depending upon the magnitude of the voltage produced in said secondary windings (37) and (38), the position of said iron core (42) being varied together with said roller (9) in accordance with the variation in the tension of said yarn (7) thereby producing a rectified d.c. output voltage at said output resistors (47, 48),

a tacho-generator (18) coupled to said three-phase induction motor (15) and connected to an associated rectifier circuit (19) having an output resistor (50) to produce a dc. output voltage corresponding to the rotational speed of said three-phase induction motor,

and, circuit means associated with said output resistors (47, 48) of said rectifier (13) and said output resistor (50) of said rectifier circuit and connected to said main control means (17) for producing the sum of said d.c. output voltage of said differential transformer l2) appearing at the output of said rectifier (13) and said d.c. output voltage of said tacho-generator (l8) appearing at the output of said rectifier circuit, whereby the flow of current through said main control means (17) is controlled by the combined dc. voltage.

2. A constant tension controller device for a winder according to claim 1, wherein said circuit means comprises a phase controlling transistor 56) connected to receive the do. outputs of said differential transformer (12) and said tachogenerator 18) a unijunction transistor (55) connected to receive the output of said phase controlling transistor (56), and a pulse transformer (59) connected to receive the output of said unijunction transistor (55) and having its secondary winding connected to the control terminal of said main control means (17), whereby when the flow of current to said phase controlling transistor (56) is controlled, the switching on of said unijunction transistor (55) is controlled so that the flow of current to said main control means (17) is controlled by the secondary output of said pulse transformer (59).

3. A constant tension controller device for a winder according to claim 2, wherein said main control means (17) is composed of a thyristor (51).

4. A constant tension controller device for a winder according to claim 2, wherein said main control means (17) is composed of a full-wave rectifier having its a.c. terminals connected in series with one phase of said three-phase power source and its d.c. terminals connected to a thyristor, whereby the flow of current through said full-wave rectifier is controlled by controlling the firing angle of said thyristor. 

1. A constant tension controller device for a winder comprising main control means (17) connected in series with one phase of a three-phase power source for controlling the flow of current therethrough, a three-phase induction motor (15) connected to said three-phase power source through said main control means (17) for driving a spool (6), a vertically movable roller (9) mounted on an arm (11) supported pivotally at supporting point (10), around which roller (9) yarn (7) is led from a supply reel through a fixed roll (8) to the spool (6), a differential transformer (12) having an iron core (42) mechanically connected with said vertically movable roller (9) and having secondary windings (37, 38), a rectifier (13), including diodes (43,44) and output resistors (47, 48) connected in series with said secondary windings (37,38) to produce across said series resistors (47, 48) a differential voltage in a predetermined direction depending upon the magnitude of the voltage produced in said secondary windings (37) and (38), the position of said iron core (42) being varied together with said roller (9) in accordance with the variation in the tension of said yarn (7) thereby producing a rectified d.c. output voltage at said output resistors (47, 48), a tacho-generator (18) coupled to said three-phase induction motor (15) and connected to an associated rectifier circuit (19) having an output resistor (50) to produce a d.c. output voltage corresponding to the rotational speed of said threephase induction motor, and, circuit means associated with said output resistors (47, 48) of said rectifier (13) and said output resistor (50) of said rectifier circuit and connected to said main control means (17) for producing the sum of said d.c. output voltage of said differential transformer (12) appearing at the output of said rectifier (13) and said d.c. output voltage of said tachogenerator (18) appearing at the output of said rectifier circuit, whereby the flow of current through said main control means (17) is controlled by the combined d.c. voltage.
 2. A constant tension controller device for a winder according to claim 1, wherein said circuit means comprises a phase controlling transistor (56) connected to receive the d.c. outputs of said differential transformer (12) and said tacho-generator (18) a unijunction transistor (55) connected to receive the output of said phase controlling transistor (56), and a pulse transformer (59) connected to receive the output of said unijunction transistor (55) and having its secondary winding connected to the control terminal of said main control means (17), whereby when the flow of current to said phase controlling transistor (56) is controlled, the switching on of said unijunction transistor (55) is controlled so that the flow of current to said main control means (17) is controlled by the secondary output of said pulse transformer (59).
 3. A constant tension controller device for a winder according to claim 2, wherein said main control means (17) is composed of a thyristor (51).
 4. A constant tension controller device for a winder according to claim 2, wherein said main control means (17) is composed of a full-wave rectifier having its a.c. terminals connected in series with one phase of said three-phase power source and its d.c. terminals connected to a thyristor, whereby the flow of current through said full-wave rectifier is controlled by controlling the firing angle of said thyristor. 